Power transmission apparatus



Dec. 31, 1963 H. F. HOBBS POWER TRANSMISSION APPARATUS 4 Sheets-Sheet 1Find Feb. 5, 1962 F G. 1 A. I

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POWER TRANSMISSION APPARATUS Filed Feb. 5, 1962 4Sheets-Sheet 3 FIG. IC.

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POWER TRANSMISSION APPARATUS Filed Feb. 5, 1962 4 Sheets-Sheet 4 FIG.1D.

Avnwrbf United States Patent 3,115,793 PQWER TRANSMISSIGN APPARATUSHoward Frederick Hobbs, Leamington Spa, England, as-

signor to Hobbs Transmission Limited, Learnington Spa, England FiledFeb. 5, 1962, 'Ser. No. 170,957 Claims priority, application GreatBritain Feb. 9, 1961 4 Claims. (Cl. 74761) This invention relates topower transmission apparatus of the kind having two input clutches whichcan be engaged independently and simultaneously, an epicyclicchangespeed gearing driving an output shaft, and re action brakes whichcan be engaged for holding required parts of the epicyclic gearing forobtaining required for obtaining required ratios. A particular exampleof such apparatus is described in the specification of our Patent No.738,590.

The object of the present invention is to facilitate obtaining four ormore forward ratios including an overdrive ratio w1hile maintaining acombination of other desirable characteristics, viz. obtaining allforward ratios with the engagement of the same input clutch, the otherclutch being additionally engaged in one forward ratio whereby change toeach forward ratio is effected without releasing one clutch and engagingthe other; the same brake is used for first forward ratio and forreverse ratio whereby the two ratios involving greatest torque can behandled by the same large capacity brake; progressive change of speedand momentum of the parts of the epicyclic gearing as the changes aremade progressively through the ratios; and able to provide the range andsteps in ratio required for road and other motor vehicles.

According to the invention the mechanism comprises first and secondinput clutches engageable separately and simultaneously, the first ofwhich is engaged in all forward ratios, said clutches driving inner andouter coaxial input shafts; epicyclic gearing including first and secondsunwheels carried by the inner input shaft and a sunwheel carried by theouter clutch shaft and a cage fixed to an output shaft and reactionbrakes connected with the gearing; said gearing including means drivablyconnecting the first sunwheel to one of said reaction brakes to producean underdrive ratio and means drivably connecting the second sunwheelwith another re action brake to provide an overdrive ratio.

The overdrive planetary pinion may be geared to the overdrive brake bymeans of a double pinion offset from the axis of the gearing and havingits smaller pinion wheel meshing with the overdrive sunwheel and itslarger pinion wheel meshing with an overdrive brake sunwheel coaxialwith the overdrive sunwheel.

The overdrive brake may be disposed coaxially with the axis of theapparatus at the output end of the gearing whilst the other brakes maybe disposed between the clutches and the gearing.

A constructional form of the invention will now be described by way ofexample with reference to the accompanying drawing which is a sectionalview of an apparatus made in accordance with the invention having sixforward ratios and reverse ratio.

The apparatus comprises first and second input or driving clutches A, B,the clutch discs of which are mounted respectively on a shaft 18 and asleeve 11 that surrounds the shaft 10. Four brakes C, D, E, F, surroundthe sleeve 11 and are disposed along the axis of the apparatus betweenthe clutches A, B, and an epicyclic gearing indicated generally by H.The gearing drives an output shaft 12 which supports, at the output endof the gearing H, an overdrive brake G.

The shaft carries first, second and third sunwheels 15, 17, 16, of which16, 17 are formed separately and "Ice 2 keyed to the shaft 10. Thesleeve 11 carries the brake C and a sunwheel 18. 16 is referred to asthe third sunwheel as this is not essential to the invention.

Surrounding the sleeve 11 are further sleeves 21, 22, 23, 24. Sleeve 21Carries the brake D at one end and a sunwheel 25 at the other end. Theoutput end of the sleeve 22 carries the cage 26 of the gearing H. Thiscage is formed with or carries parts 26A, 26B, 26C, which latter isfixed to the output shaft 12.

The sleeve 23 carries the brake E at one end and a ring gear 28 at theother end. Sleeve 24 carries the brake F and a housing 29 which in turncarries a ring gear 39. The cage 25 carries two pairs of planetaryspindles, two of which carry a triple pinion 33, 34, 35, and a spindle37 carrying a double pinion comprising pinions 38, 39. Pinion 33 mesheswith sunwheel 2S; pinion 34 with sunwheel 18; pinion 35 meshes withpinion 39; and underdrive ratio reaction pinion 39 with sunwheel .15.The ring gear 28 meshes with pinion 38.

The cage H carries two further pairs of planetary spindles and pinionsof which only one of each is shown, viz. spindle 48 carrying pinion 41meshing with ring gear 30 and spindle 42 carrying -a double pinioncomprising a small reaction pinion 43 meshing with sunwheel 17 and alarger overdrive reaction pinion 44 meshing with an overdrive reactionsunwheel 45 on a sleeve 46 co axial with the gearing taxis and carryingthe overdrive reaction brake G.

The brakes and brake sleeves and cage are all coaxial with the inputshafts 1t), 11, and the spindles 32, 37, 4d, 42, are all offset from theaxis of the input shafts.

In the axial direction of the gear it will be seen that the reactionbrakes C, D, E, F, for underdrive ratios are located between theclutches A, B, and the epicyclic gearing; the epicyclic gearing islocated between the underdrive brakes on the input side and theoverdrive brake G on the output side; the spindles 32, 37, are in thesame axial position as each other; and the spindles 40, 42, are in thesame position as each other but offset from the spindles 32, 37.

When clutch A and brake G [are engaged the pinions 43, 44, cause thecage 26 (and with it the output shaft) to run at overdrive speeds.

The ratios are obtained by engaging the clutches and brakes as follows:

First ratio clutch A and brake E engaged.

Second ratio clutch A and brake F engaged.

Third ratio clutch A and brake D engaged.

Fourth ratio clutch A and brake C engaged.

Fifth ratio both clutches A and B engaged.

Sixth (overdrive) clutch A and brake G engaged.

Reverse ratio clutch B and brake E engaged.

If only five forward speeds (including overdrive) are required the gears41, 3d, and brake F may be omitted.

If only four forward speeds (including overdrive) are required the gears28, 38, can be omitted.

The engagement of the clutches and brakes may be effected as describedin the specifications of our prior British Patents Nos. 628,499,628,523, 637,251, 643,499, 673,737, 738,588, 777,871, 784,724 and803,874.

I claim:

1. A power transmission mechanism comprising a housing, first and secondinput clutches, first and second input shafts connected respectivelywith said clutches, the first input shaft being located coaxially withinthe second input shaft first and second sunwheels carried by the firstinput shaft; an output shaft, a rotary cage connected to the outputshaft, at least three pinion members carried by the rotary cage on anaxis offset from the axis of the rotary cage, these pinion membersincluding a triple pinion member, an underdrive ratio pinion member andan overdrive ratio double pinion member; a first reaction sun- Wheelmeshing with the first pinion of the triple pinion, another sunwheel onthe second input shaft meshing with the second pinion of the triplepinion member; said first sunwheel meshing with a pinion of theunderdrive ratio pinion member, which latter mentioned pinion alsomeshes with the third pinion of the triple pinion member; said secondsunwheel meshing with the first pinion of the overdrive double pinionmember; a second reaction sunwheel meshing with the second pinion of theoverdrive double pinion member, an underdrive reaction brake carried bythe housing and acting on to the first reaction sunwheel; and anoverdrive reaction brake carried by the housing and acting on the secondreaction sunwheel.

2. A power transmission mechanism as claimed in claim 1 wherein the cageis disposed between the clutches and reaction brakes on the input sideand the overdrive brake on the output side, the spindle carrying theoverdrive double pinion member being also located on the output side.

3. A power transmission mechanism as claimed in 4 claim 1 having aspindle carried by the cage, a pinion on said spindle, a third sun-wheelon the first input shaft meshing with said spindle, a ring gear meshingwith said last mentioned pinion, and a further underdrive reaction brakecarried by the housing and acting on said second ring gear.

4. A power transmission mechanism as claimed in claim 1 having a secondunderdrive pinion connected to the aforesaid underdrive pinion member, aring gear meshing With said second underdrive pinion, and a furtherreaction brake carried by the housing and acting on said :ring gear.

References Cited in the file of this patent UNITED STATES PATENTS2,803,974 Kelley Aug. 27, 1957 FOREIGN PATENTS 384,880 France Apr. 24,1908 586,165 Canada Nov. 3, 1959 789,430 Great Britain Oct. 11, 1961

1. A POWER TRANSMISSION MECHANISM COMPRISING A HOUSING, FIRST AND SECONDINPUT CLUTCHES, FIRST AND SECOND INPUT SHAFTS CONNECTED RESPECTIVELYWITH SAID CLUTCHES, THE FIRST INPUT SHAFT BEING LOCATED COAXIALLY WITHINTHE SECOND INPUT SHAFT FIRST AND SECOND SUNWHEELS CARRIED BY THE FIRSTINPUT SHAFT; AN OUTPUT SHAFT, A ROTARY CAGE CONNECTED TO THE OUTPUTSHAFT, AT LEAST THREE PINION MEMBERS CARRIED BY THE ROTARY CAGE ON ANAXIS OFFSET FROM THE AXIS OF THE ROTARY CAGE, THESE PINION MEMBERSINCLUDING A TRIPLE PINION MEMBER, AN UNDERDRIVE RATIO PINION MEMBER ANDAN OVERDRIVE RATIO DOUBLE PINION MEMBER; A FIRST REACTION SUNWHEELMESHING WITH THE FIRST PINION OF THE TRIPLE PINION, ANOTHER SUNWHEEL ONTHE SECOND INPUT SHAFT MESHING WITH THE SECOND PINION OF THE TRIPLEPINION MEMBER; SAID FIRST SUNWHEEL MESHING WITH A PINION OF THEUNDERDRIVE RATIO PINION MEMBER, WHICH LATTER MENTIONED PINION ALSOMESHES WITH THE THIRD PINION OF THE TRIPLE PINION MEMBER; SAID SECONDSUNWHEEL MESHING WITH THE FIRST PINION OF THE OVERDRIVE DOUBLE PINIONMEMBER; A SECOND REACTION SUNWHEEL MESHING WITH THE SECOND PINION OF THEOVERDRIVE DOUBLE PINION MEMBER, AN UNDERDRIVE REACTION BRAKE CARRIED BYTHE HOUSING AND ACTING ON TO THE FIRST REACTION SUNWHEEL; AND ANOVERDRIVE REACTION BRAKE CARRIED BY THE HOUSING AND ACTING ON THE SECONDREACTION SUNWHEEL.